Part of diving is a dive buddy.
It's an idea of mutual support in case something goes wrong there's someone there who can help.
I never learned to dive because if something goes wrong there won't be anybody there who will help.
I am that charming.
When you realize that someone would let you drown rather than have to sit with you on the boat trip back, you stop being interested in diving.
When you realize you can get a complete stranger to the "let Thag drown" point on the trip OUT, you start actively avoiding boats as well as diving.
My eulogy will probably contain words to the effect of, "we're not surprised this happened, we're just shocked it took so long."